A resist composition has attracted attention as a material to form a permanent film for e.g. partition walls between pixels of a color filter, partition walls between pixels of an organic EL (electro-luminescence) display device, partition walls partitioning TFTs (thin film transistors) of an organic TFT array, partition walls for ITO electrodes of a liquid crystal display device, and partition walls of a circuit wiring substrate.
Further, a low cost process utilizing ink jet recording technology of injecting a liquid by an ink jet after formation of the above partition walls, has been proposed.
For example, in the production of a color filter, an ink jet method has been proposed to jet and apply R (red), G (green) and B (blue) inks within fine pixels. Here, formation of a pixel pattern is carried out by photolithography using a resist composition, and a coating film cured product of the resist composition is utilized as partition walls between pixels.
Further, in the production of an organic EL display device, an ink jet method has been proposed wherein a solution of a hole transport material or a luminescent material is jetted and applied to form hole transport layers or luminescent layers within fine pixels. Here, formation of a pixel pattern is carried out by photolithography using a resist composition, and a coating film cured product of the resist composition is utilized as partition walls between pixels.
Further, in the production of an organic TFT array, an ink jet method has been proposed wherein a solution of an organic semiconductor is jetted and applied. Formation of partition walls partitioning TFTs is carried out by photolithography using a resist composition, and a coating film cured product of the resist composition is utilized as the partition walls.
Further, in the production of a liquid crystal display device, an ink jet method has been proposed wherein an ITO (tin doped indium oxide) solution or dispersion is jetted and applied to form ITO electrodes, and formation of an ITO electrode pattern is carried out by photolithography using a resist composition, and a coating film cured product of the resist composition is utilized as partition walls.
Further, in the production of a circuit wiring substrate, an ink jet method has been proposed wherein a metal dispersion is jetted and applied to form circuit wirings. Here, formation of a circuit wiring pattern is carried out by photolithography using a resist composition, and a coating film cured product of the resist composition is utilized as partition walls.
In the ink jet method, it is necessary to prevent e.g. color mixing of inks between adjacent pixels, or to prevent the material jetted by an ink jet from attaching to or solidifying at portions other than the predetermined regions. Accordingly, the partition walls are required to have repellency against water or an organic solvent constituting the ink jet coating solution, i.e. a so-called ink repellency.
Accordingly, a resist composition to form partition walls having an ink repellency has been proposed. For example, Patent Document 1 discloses a photosensitive resin composition comprising a silicon-containing resin having a polyfluoroalkyl group, a polydimethylsiloxane group and an ethylenic double bond.
However, if partition walls for e.g. a color filter, an organic EL display device or an organic TFT array is prepared by using a composition to impart such an ink repellency, so-called edge leakage is likely to take place wherein the thickness of the ink layer in the vicinity of partition walls becomes thin, and the periphery of the partition walls look white.
When partition walls are formed by a coating film cured product of a resist composition, the resist composition at a portion to be dots (regions within which an ink is to be injected, surrounded by the partition walls) is removed in a development step. However, if a resist composition to impart ink repellency to the partition walls is used, if its removal is insufficient, the residue of the composition will adversely affect the ink injection, and such is one cause of the above edge leakage. Further, the partition walls are made of a coating film cured product of the resist composition, and molecules which did not undergo curing reaction remain in the partition walls, and such molecules migrate from the partition walls to the dots and contaminate the dots in the subsequent post-baking step, and such contamination is also considered to be one cause of the above edge leakage.
In order to prevent the edge leakage, for the purpose of removing impurities remaining in the dots after formation of the partition walls, for example, it is considered to carry out an ink affinity-imparting treatment such as cleaning with an alkali aqueous solution, UV cleaning, UV ozone cleaning, excimer cleaning, corona discharge treatment or oxygen plasma treatment. However, if an ink affinity-imparting treatment is carried out by such a method, the ink repellency of the partition walls is also decreased. As a method of carrying out an ink affinity-imparting treatment without decreasing the ink repellency of the partition walls e.g. by UV cleaning, Patent Document 2 proposes a method of protecting the partition walls with a resin, but this method is complicated since a step of removing the resin is required. Further, Patent Document 3 proposes use of a siloxane compound having a specific structure as a UV ozone-resistant resin, but there may be a problem in the adhesion to a substrate since it is a positive composition.
Therefore, a negative photosensitive composition for formation of partition walls of an optical device, having ink repellency capable of withstanding an ink affinity-imparting treatment such as UV ozone cleaning and at the same time capable of forming dots excellent in the ink wettability, has been desired.